Pressure-release mechanism



April 21, 1942. T. I. STEPHENSON. JR ,7

PRESSURE-RELEASE MECHANISM Filed June 8, 1939 --+---L----------- :1 l l 0.25 J l Jig-1.

I INVENTOR Thomas Sfep/renson Jr:

Patented Apr. 21, 1942 PRESSURE-RELEASE MECHANISM Thomas I. Stephenson, Jr., Maryville, Tenn., as-

signor to Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Application June 8, 1939, Serial No. 278,071

4 Claims.

My invention relates to apparatus for releasing the pressure in metal working machines, such as rolling mills and the like, wherein high working pressures are employed, and more 'particularly to breaker blocks or devices having a confined pressure-transmitting medium which may be displaced to release the working pressure.

One object of my invention is to provide a pressure-release device of such form that it will be capable of withstanding the high initial shock pressures when the work enters the rolls of a rolling mill without affecting the gauge or draft, and which can be actuated to effect relief or dissipation of working pressures very rapidly. Another object of my invention is to provide a pressure-release breaker block having a confined solid pressure-transmitting member therein that is composed of a material not affected adversely by temperature and pressure changes, together with means for effecting displacement, as by extrusion, of the member to effect positive release of the pressure. A further object of my invention is to provide a device of the foregoing type of generally simplified and improved form.

In the accompanying drawing illustrating a preferred form of my invention:

Fig. l is a plan view of the device;

Fig. 2 is a view taken on the line II-II of Fig.

Fig. 3 is a plan view of the pressure-transmitting member employed in the structure of Fig. 2; Fig. 4 is a view to an enlarged scale taken on the line IV-IV of Fig. 3; and

Fig. 5 is a vertical, transverse sectional view of a portion of a rolling mill, showing one man- L ner in which my invention may be applied thereto.

Referring first to Fig. 5, I have shown one side of a typical rolling mill having rolls 5 and 6.

The rolls are supported at their necks I and 8 in suitable bearings 9 and II], respectively, in somewhat the usual manner common to rolling mill structures. The upper bearing or rider 9 for the roll 5 receives my improved breaker device thereon, which device is indicated generally by the numeral I2. The usual breaker block or device employed in rolling mills is removed and my improved breaker device I2 substituted therefor. housing nut I I and bears against the top of the pressure-release device. The nut I4 is carried by the mill housing I5. It will be understood, of course, that'the parts thus far described will be duplicated at the other end of the rolls, or applied Pressure screw I3 is threaded through the to other types of machinery.

power-driven mechanism of any suitable well known form.

Referring now more particularly to Figs-1 to 4, the breaker device comprises a bottom or base plate It having an upstanding boss H on its upper face. The plate I6 is adapted to be disposed on the rider 9 of the bearing for the upper roll 5, as heretofore described, and it is preferably provided with a pair of rails or shoes I9 that are spaced apart such distance as to embrace the sides of the rider member 9. These rails prevent rotation of the base plate I6 relative to the bearing 9.

A pair of retainer blocks 20, each having a semi-circular recess formed in one face thereof,

is loosely carried or supported on the upper side of the plate I6. The blocks 20 are adapted to be brought together with their recessed faces in abutting relation and in embracing relation to the member I'I, thereby forming an axially divided cylinder which is closed at its lower end by the seating disc I I. The blocks are releasibly retained in such closed position by means of a pair of through-bolts 2| which extend through apertures bored through the blocks adjacent to their lateral edges. The bolts 2| are provided with nuts 22, whereby clamping pressure may be applied or released.

Seated on the member I! within the cylinder 7 formed by the recessed blocks 20 is a pressurerelease member composed of an inert material capable of being displaced, as by extrusion, under pressure. In the preferred embodiment of the invention the pressure-release member takes the form of a flat disc 23 of soft metal, such as lead, aluminum, tin, etc., or alloys of these relatively soft metals. This disc is preferably made of pure lead, and before being inserted its top and bottom faces are preferably coated with a suitable lubricant, SL'Ch as graphite grease, so that when the lead is displaced, as hereinafter described, friction will be reduced to a minium. A piston 24 is slidabl supported in the cylinder and rests upon the top of the disc 23, the top face of the piston 24 being concave to form a substantially spherical seat for the mill screw I3.

The unit I2 thus assembled is seated upon the bearing cap or rider of the top roll, with the axes of the bolts 2| parallel with the axis of the roll so that the nuts 22 will be accessible through the windows of the roll housings. At the end of the structure adjacent to the rolls, the block 20 carries a guide bar 25 which extends past the heads The screws are. adapted to be actuated either manually or by of the bolts 2|, so that when the nuts 22 are loosened, the bolts will not move into contact with the end faces of the rolls and cause damage thereof. The bottom plate I6 is also provided with an open ended slot 26 into which extends a guide pin 21, carried bythe outermost block 20. Thus, when the mill screw I3 is rotated, the blocks 20 will be held against rotation by means of the pin 21 and through engagement of the blocks with the upstanding boss or seat II. On the other hand, the slot and pin connection 26-21 permits sliding movement of the blocks 20 relative to the plate l6 upon release of the nuts 22.

Preliminary to the use of the devices after they have been assembled in the manner thus described, pressure is applied to the column, consisting of the seat member H, the lead disc 23. and the piston 24, so as to cause the lead to flow and fill out any voids that might be present between th bottom plate I! and the piston 24. Thus, when the device is placed in service, the screws may be actuated and the rolls positioned or set accurately with respect to their gauge and draft. If at any time a jam or sticker occurs, or when the mill is otherwise stopped with metal between the rolls. the nuts 22 may be quickly loosened or backed off, whereupon the high working pressure of the mill will cause the lead to extrude radially from between the seat l1 and the piston 24. It will be seen that there is no sudden release of pressure since, as the clamping pressure on the block 20 is lessened, the blocks will move apart to a degree determined by the lessenin of the clamping pressure, whereupon the lead first extrudes between the abutting faces of the'blocks 20. If necessary, heat may be applied to the disc 23 to soften or melt the same, thus effecting a more rapid release of pressure. After the pressure has been relieved, it is obvious that the screws l3 may be backed off or retracted very rapidly, since they will be free of pressure, and the used breaker member 23 quickly removed and a new one substituted therefor. Thus the time required to free the rolls and to restore the equipment to operating condition is reduced to a minimum.

I have found that, even though employing a metallic disc of soft metal, such as lead, for the pressure-transmitting medium, under the high pressures encountered in rolling mill practice, the lead tends to extrude slightly along the lines between the abutting faces of the block members 20. In order to prevent this finning of the material 23, I preferably enclose the same in a metal ring 28 which may suitably be formed of thin gauge aluminum or other metal which is slightly harder than the material 23. The lead disc may be conveniently cast within the sealing ring 28.

By thus enclosing the periphery of the member .23, the ring will span the joints between the blocks 20 and thereby effectively prevent the finning above mentioned. When the blocks 20 are released to permit lateral displacement or extrusion of the member 23, ordinarily the ring 28 will expand sufficiently to cause it to break, but in case it does not do so, it is merely necessary to' cut it, which can be readily effected by means of a cold chisel.

The provision of the separable block members 20 represents an important feature of the pressure-release mechanism of this invention. These locks serve, when closed, to prevent spreading of the pressure-transmitting material 23, while, on

sure medium. Furthermore, during'normal 'operation of a. rolling mill incorporating the pressurerelease mechanism of this invention, there is no tendency to develop lateral pressures or side set on the mill housings.

The pressure material 23 is normally positioned intermediate the ends of the chamber formed by the members 20, it being supported from below by the upstanding boss or spacer block I1, so that there is little likelihood of leakage of the material along the walls of the chamber.

After a breaker block has been removed from the mill, the extruded material can be removed from the various parts and the structure reassembled with a new disc 23 incorporated therein, which, after having been subjected to'preliminary pressure conditions in order to expand the new disc, is ready for use when needed.

It is to be understood that the invention may be practiced otherwise than as specifically illustrated and described, since it can be employed advantageously in, connection with machinery other than rolling mills, such as screw-presses, roller levelers, straighteners, etc., wherein the operating mechanism is liable to frictionally freeze under high working pressures.

Various modifications may be made in the invention without departing from the spirit thereof, or the scope of the claims and, therefore, the exact form shown is to be taken as illustrative only and not in a limiting sense, and it is desired that only such limitations shall be placed thereon as are imposed by the prior art, or are specifically set forth in the appended claims.

What I claim is:

1. A pressure-release mechanism comprising an axially divided cylinder open at its ends, clamping means cooperating with said cylinder for releasably securing it in closed position, a metallic plastically-deformable pressure-transmitting material within said cylinder, means disposed in said cylinder at opposite ends thereof for confining the pressure-transmitting material therebetween and subjecting it to working pressure, said clamping means being operable to release said cylinder for radial movement relative to said material and said confining means, whereby to permit displacement of said pressure-transmitting material and to relieve said working pressure.

2. A pressure-release breaker device comprising a base plate, a pair of block members slidably supported on said plate, each of said blocks hav- 7 ing a semi-circular recess formed in one face thereof to form a cylinder open at its end when said blocks are brought together, a pair of clamping bolts extending through said pair of blocks for releasably holding them together, a spacer member secured to said base plate and extending upwardly into the lower end of said cylinder, 8. disc of soft metal on said spacer member, and a piston engaging the top of said disc, said device being subjected to a preliminary compressing force, thereby to spread said disc and fill any voids present between the piston, the spacer member and the adjacent wall of the cylinder.

3. A pressure-release breaker device adapted to be interposed between the adjusting screw and the bearing rider of the top roll of a rolling mill, said breaker device comprising a base plate seated on said rider, parallel rails on the under side of said plate in engagement with the sides of the said rider, a pair of block members slidably supported on said plate, each of said blocks having a semi-circular recess formed in one face thereof to form a cylinder open at its ends when said blocks are brought together, a pair of clamping bolts extending through said blocks in directions parallel to the axis of the said top roll, a spacer disc in the lower end of said cylinder and secured to said plate, a lead disc on said spacer disc, a piston in engagement with said lead disc and the lower end of said adjusting screw, said disc and said piston being disposed co-axially of said screw, and a pin and slot connection between one of said blocks and said base plate.

4. A pressure-release device comprising a pair of disc members and an intermediate soft metal disc assembled in axially stacked relation and adapted to be subjected to compressive working pressure, said intermediate disc being incapable of sustaining said pressure without plastic deformation in radial directions unless peripherally supported, and supporting means completely encircling said stacked discs in engagement with the periphery thereof for restraining said intermediate disc against deformation, said supporting means being movable relative to said stacked discs, at will, out of said restraining position to form a circumferential discharge passage into which the metal of said intermediate disc is displaced under said pressure.

THOMAS I. STEPHENSON, JR. 

